


Rin's Little Secret

by dramaticaltrash



Category: Free!
Genre: Diapers, Infantilism, M/M
Language: English
Status: Completed
Published: 2015-06-26
Updated: 2015-06-26
Packaged: 2018-04-06 08:12:34
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,795
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4214571
Author URL: https://archiveofourown.org/users/dramaticaltrash/pseuds/dramaticaltrash
Summary: <blockquote class="userstuff">
              <p>Matsuoka Rin is your average Samezuka teen who has a secret, what happens when former captain Seijuurou finds out about it?</p>
            </blockquote>





	Rin's Little Secret

Rin’s Little Secret: Seijuro Mikoshiba x TBDL! Matsuoka Rin

(This is my first time writing a fanfic, please take it easy on me!  
Also, Rin somehow managed to buy some safety rails for his bed so he made it look like a crib)

Matsuoka Rin had a secret. He was an TBDL, a Teen Baby Diaper Lover. He never thought he would get into this. He had been doing this for two weeks straight without anyone noticing, not even his sister, Kou or his roommate Nitori. Rin laid down on his bed, sticking a pacifier into his mouth and began sucking on it,remembering the day he decided to have a second childhood.

~Flashback brought to you by Merman Haru! (WARNING! ITS SUPER LONG!)~

“Ahhh…. mmh…” Rin moaned, watching the two girls on his laptop make out and do naughty things to each other. Then, the unexpected happened. His current computer tab closed itself. “Oh, COME ON! It was just starting to get good!” Rin shouted at his laptop. “Eh? What’s this?” He asked himself as he clicked on a blank page only showing a link. “ ‘Find TBDL’S in your area?’ What’s a TBDL?” He opened up a new tab and found the meaning of TBDL. “Ok, I’ve seen a lot of weird things, but this one is by far the weirdest shit I’ve ever seen.” He then searched for what TBDL’s do. 

He found out that they do the exact same thing as normal babies do. “Huh, reliving childhood. Must be nice for them… I suppose I could try it, I haven’t had anyone really take care of me since Mom and Dad passed away.” He said to himself. “Ah, what the hell? I’ve done crazy shit before, why should this one be any different?” He asked himself, cleaning up and grabbing his car keys. He got into his car and drove off to the store. Once he entered the store, he grabbed a basket and went straight to the infant isle. There were the things he needed, pacifiers,  
baby food, all of that. He grabbed about a two week’s worth of baby food, a package with two pacifiers that were big enough to fit in his mouth, bottles, wipes and powder

He then moved onto the adult care isle and grabbed three packs of Abena M4 diapers. Rin knew he was a medium. He then headed to the checkout. “Do you have any kids?” The cashier asked Rin. “No! Uh, my Aunt told me to run to the store and get some more food for Rena, my little sister. The Abenas are for my grandmother.” “Well that’s very nice of you!” “Thanks.” Rin said as he paid for the items and headed out to the car.

~FLASHBACK END!~

Now here he was, lying down on his bed, sucking on a pacifier. 'I could definitely get used t-' “Rin! Are you there? You haven’t been yourself for a while.” Rin knew that voice, it was none other than his boyfriend, Mikoshiba Seijuro. “I’m coming in…” Seijuro said. ‘Well, he was gonna find out sooner or later.’ Rin thought to himself. “R-Rin? What is all this?” Seijuro asked in shock. Rin sighed and explained everything to his coach. “I see, would you like me to be your ‘Daddy’?” Seijuro asked. “Yeah, if you don’t mind, that is…” Rin said quietly. 

Seijuro smiled. “Of course not, you’re my little boy.” Seijuro explained. “Daddy!” Rin exclaimed. “Hey… where’s your diaper, huh?” Seijuro whispered. Rin simply pointed to his closet. Seijuro pulled out the necessary supplies for Rin and began diapering him. “There we go, all done.” “Thanks daddy…” Rin said. “Want me to get you a bottle?” Rin nodded and waited for his boyfriend to return. Seijuro returned with a warm bottle of milk in his hand. “Alright, Rin, come here sweetie.” Seijuro said patting his lap gently. Rin crawled over to him and let his boyfriend pick him up and set him on his lap, cradling him in the process. “Drink up, baby.” Rin gently put his lips on the nip and began sucking the warm milk that was inside. He had missed this feeling so much, he forgot what it was like to be bottle-fed. Seijuro gently pet his hair, watching the maroon-haired teen drink his milk in a cute manner. About ten minutes later, Rin had finished his bottle.

“Boy, you were hungry, weren’t you bud?” His captain asked. He picked up the oversized baby and began patting his back until he let out a loud belch. “There we go…” Mikoshiba chuckled. “Me wanna watch TV.” Rin said, sticking his pacifier into his mouth. “Ok, wanna watch swimming?” The fire-head male asked. Rin nodded in excitement. “Ok. But first we need to lay down some rules.” Seijuro began. “  
1\. When we’re alone, you have to call me daddy.  
2\. You will not be allowed to eat grown-up food unless I say its ok or I will let you have it if you’re good.  
3\. You will have early bedtimes and naps during the day, if a teacher asks, I will say that you are not feeling well and I will say that I need to watch over you.  
4\. If you use any foul language or watch anything with adult content, you will be spanked.  
Lastly, you will be in diapers 24/7 during school and when practice is over. Bathroom is off limits, unless I'm giving you a bath and you are only allowed to go to the bathroom in your diapers. Ok, baby?” His captain asked in a polite manner. "Yes daddy." Rin said, hugging  
Seijuro's leg. "Alright then, let's watch some TV."

~45 Minutes later~ 

“Mmnh…” Rin moaned, a pain moved throughout his stomach. “Rinny? What’s wrong? Need to go to the restroom?” Rin nodded, tears threatening to fall. “Just let it out baby, I will be more than happy to change you afterwards.” Rin hesitated, but knew there was no choice. “Don’t look. Please.” Rin pleaded. Seijuro simply turned away and let Rin do what he needed to do. Rin grunted in pain, slowly pushing the mess out of his body and into his diaper. After he had finished doing that, he started wetting himself. Since he was known to heavily wet the bed as a child due to severely weak bladder control, he wet himself for about a minute. Rin started crying softly. Seijuro turned around and brought him into a hug. “Shh, shh, its ok, its ok. Let’s get you changed, okay?” Rin nodded, letting his boyfriend lay him down on a plastic changing mat. “You really had to go, didn’t you?” The coach asked, removing the full diaper. Rin simply, blushed and looked away. “Aw, don’t be like that, its perfectly normal.” He stated wiping his rear, putting cream on and powdering him. “There, all done.” Seijuro said, fastening the new diaper on.

“Thank you daddy…” Rin said, hugging his daddy. “You’re welcome baby.” His now smiling boyfriend said picking him up and tucking him in. “I’m right across the hall, cry if you need anything ok?” He said. “Daddy?” “Yes baby?” Rin gave him a baby monitor, and let his daddy plug it in. “That’s so I don’t wake the others.” Rin said, blushing. “Thank you baby.” Seijuro said, walking into his room and closing the door. Little did Rin know, that his room-mate was unlocking the door to his room. “Senpai? I’m back.”

Rin sat up and took the pacifier out of his mouth. “Hey Ai.” “Senpai? Why do you have a pacifier?” Rin explained what he had been doing behind Nitori’s back, fearing that Nitori would begin bullying him. “I see, so Mikoshiba-senpai is your ‘Daddy’, I could be your Onii-chan.” Nitori said smiling softly. “Really? You don’t mind?” Nitori shook his head. “Not at all. Besides, this tbdl stuff makes you look really cute.” Nitori said blushing a bit. Rin smiled back at him. “Thanks Nit- Onii-chan.” “I’ll be on the top bunk, but I might not wake up,  
as I mentioned in the past, I’m a pretty heavy sleeper.” Rin nodded in agreement. “Night baby.” Nitori said softly. Rin placed is pacifier back in his mouth. “Nigh-nigh.”

~11:45 pm~

It was pouring rain outside, and with pouring rain comes thunder. Rin had always hated thunderstorms. It reminded him of the day his father entered the navy and died in battle. What’s worse is that thunder scared the daylights out of Rin, making him wet uncontrollably. ’Take it easy Rin. I-its just a storm, it can’t get you. Just take deep breaths…’ Rin though to himself. “BOOM!” A loud clap of thunder frightened the oversized baby, making him wail for his boyfriend. “SEIJURO! DADDY! HELP!” Luckily he didn’t wake any of the other dorms, if they found out his secret, they would bully him forever. Seijuro opened the door and made his way over to Rin, lowering the safety bars so he could comfort him. “Aww Rin…” Seijuro felt bad for him, no baby should have to listen to thunderstorms. “DADDY!” Rin wailed. “Shhh, shhh, daddy’s here, daddy’s gotcha.” Rin buried his face into his boyfriends shirt. “Let’s change your diaper, okay hun?” Seijuro whispered to the shark-toothed teen. “Mm-hm…” Rin whimpered softly. He was quiet during the diaper change.

“Come on Rin, you’re sleeping with me tonight.” Seijuro said to him. “W-weally?” “Yeah, daddy will protect you.” Seijuro picked up Rin and carried him bridal style to his room. Rin gasped softly, right in front of him was a crib, a changing table, and a mobile hanging over the crib. “I knew you’d like it…” Mikoshiba said as he kissed Rin’s forehead. “Do you want me to sing to you?” Seijuro asked the crying boy? Rin just nodded, tears streaming down his face. 

Saa wasuremashou sono mirai ga  
Mata chirurarete yuku nante  
Namanurui kaze doguro wo maitara  
Sore ga tabun aizu

Nukedashitette Nukedashitette  
Kanashisugiru unmei kara  
Anata wa naraku no hana ja nai  
Sonna basho de  
Sakanaide sakanaide  
Karametorarete ikanaide

Oto mo naku tobikau toki no kakera

Dare ga kono te wo nigitteru no?  
Dare ga kono kami wo nadeteiru no?  
Ima naiteita moegi no naka de  
Kanjiteru aizu

Tobikoetette tobikoetette  
Unmei no haguruma kara  
Anata wa naraku no hana ja nai  
Sonna basho de  
Chiranaide chiranaide  
Soshite tane wo nokosanaide

Me wo daseba futatabi mawaru karma

Nukedashitette Nukedashitette  
Kanashisugiru unmei kara  
Anata wa naraku no hana ja nai  
Sonna basho de  
Sakanaide sakanaide  
Karametorarete ikanaide

Oto mo naku tobikau toki no kakera  


When he finished singing, Seijuro looked at the now sleeping teen, he was cute when he was asleep. 

'I think I’ll get used to this whole ‘Daddy’ idea.' Seijuro thought to himself.  
This was Rin’s little secret.

END

**Author's Note:**

> Ok this is my first time posting a fanfic on here so please be respectful.  
> Hate comments will be burned
> 
> Song that Seijuurou sang: https://www.youtube.com/watch?v=rT1Rj5mDCrQ


End file.
